Improved Interface Stability of High-Entropy Perovskite Anodes for Advanced Aqueous Alkaline Battery-Supercapacitor Hybrid Devices

Abstract

High-entropy perovskite oxides with phase separation experience poor cyclic stability during energy storage processes, hindering their applications in aqueous alkaline battery-supercapacitor hybrid devices. Herein, the synergistic effect of multiple elements in La0.7−ySryBi0.3Mn0.4−xFe0.3Cu0.3CrxO3 on ion-diffusion kinetics and surface-cation conversion is regulated by Cr and Sr to optimize the cyclic stability. A novel sandwich composite structure "carbon paper (CP)/high-entropy perovskite oxide/reduced graphene oxide (rGO)" is designed. The obtained La0.56Sr0.14Bi0.3Mn0.3Fe0.3Cu0.3Cr0.1O3 (Cr,Sr-HEPO) exhibits good cyclic stability owing to improved reversibility and suppressed cation leaching. Furthermore, the rGO of CP/Cr,Sr-HEPO/rGO suppresses the cation leaching and the structural characteristics of rGO also improve the reversibility of hydrogen-ion (de)intercalation in Cr,Sr-HEPO. The resulting CP/Cr,Sr-HEPO/rGO anode illustrates 531.93 C g−1 at 0.5 A g−1 coupled with high capacity retention of 69.39% after 5000 cycles at 10 A g−1. Overall, the proposed design strategy looks promising for improving the interfacial stability of high-entropy perovskite oxides during energy storage.

Keywords: high-entropy perovskite oxides, reduced graphene oxide, supercapacitors, Composite, cyclic stability